Light-controlling device for photographic-printing machines



Apr. 24, 1923 W. D. WOOD LIGHT CONTROLLING DEVICE FOR PHOTOGRAPHIC PRINTING MACHINES Filed Oct. 12

Fwy/707.29. mod 61 H 01mm Patented Apr. .24, 1923.

UNITED STATES PATENT ore cs.

WILLIAM D. WOOD, OF SEATTLE, WASHINGTON, ASSIGNOR TO SPECIALTY MANUFAC- TURING COMPANY, OF SEATTLE, WASHINGTON, A CORPORATION OF WASHINGTON.

LIGHT-CONTROLLING DEVICE FOR PHOTOGRAPHIO-PBINTING IYIACHINES.

Application filed October 12, 1920. Serial No. 416,487.

T all whom it may concern:

Be it known that I, WILLIAM D. Woon, a citizen of the United States, residing at Seattle, in the county of King and State of Washington, have invented certain new and useful Improvements in Light-Controlling Devices for Photographic-Printing Machines, of which the following is a specification.

This invention relates to apparatus for making photographic prints and more particularly to improvements in certain electric switch mechanism used in such apparatus for opening and closing the circuit. to the lamps by which the exposures of the prints are made.

The object of my improvements is to provide a novel and convenient switch by which the lamp circuit may be instantaneously broken thereby avoiding arcing between the switch terminals and enabling the operator to accurately time an exposure.

Further objects are to provide switch mechanism which is simple in construction, reliable in operation, inexpensive to manufacture, and which is especially designed for use with a photographic printing cabinet having a hinged cover which serves as the printing frame.

WVith the above and other objects in view, the invention consists in the novel construction, adaptation and combination of parts as will be hereinafter described and claimed.

In the accompanying drawings, Figure 1 is a plan view of a photographic printing device constructed in accordance with this invention. Fig. 2 is a view in front eleva tion of the same showing parts of the front wall of the lamp housing broken away. Fig. 3 is a sectional view taken substantially on a broken line 33 of Fig. 1. Fig. 4 is an underside plan view of the electric switch in its preferred form and shown attached to a part of the frame. Fig. 5 is a. fragmentary plan view of the top of the device illustrating the switch controller in a different position from that in which it is shown in Fig. 1. Fig. 6 is a sectional view taken substantially on broken line 6-6 of Fig. 5. Fig. 7 is a wiring diagram of the lamp circuit.

Referring to the drawings the numeral 7 designates a printing frame or table having a central opening 8 for a glass plate 10.

Connected to the frame 7 by hinges 11 is a frame '12 carrying a platen 13 which is mounted somewhat loosely therein so as to automatically adjust itself to fit fairly over the top of the plate to retain a piece of sensitized print paper in contact with a photographic film or plate in a well known manner.

The table 7 is mounted upon a housing 14 within which are disposed electric lain-p bulbs 15 that are connected with the wires 16 and 17 of an electric circuit.

Secured to the under side of the table is a block 18 of insulating material and from which extend downwardly three resilient switch terminals 20, 21 and 22, which are ar ranged in substantially the relative positions shown in Fig. 1. The switch terminals 21 and 22 are connected as shown in Fig. 7 to the circuit wire 16. Each of said terminals desirably are formed with their lower extremities bent or rolled inwardly as at 23 to facilitate making electrical engagement with a roller 24.

This roller is rotatably mounted on a pin 25 supported in a bifurcated attachment 26 at the lower end of a post 27 which extends upwardly through a tubular guide 28 provided in the table 7. As shown the post 27 is provided between the bracket 26 and the block 18 with a collar 29 engageable with the guide 28 for limiting the upward move ment of such post. The roller 24.- is urged upwardly into the position in which it is shown in Fig. 6 by springs 30 that are connected to the block 18 and to the ends of the pin 25. see Fig. 8.

A trip member or controller 31 is pivotally connected intermediate its length to a post that is rigid with and extends downwardly from the front bar member of the platen frame 12.

Thetrip member 31 is formed to provide at one end an upturned stop element 33 and at the other end an upturned finger piece 34.

The controller is yieldingly held in the position in which it is represented in Fig. 1 by means of a spring having one of its ends secured to the trip member and its other end secured to the platen frame 12.

For operating. said frame is tilted into its dotted line position 12 Fig. 3 to receive the sensitized paper and is then turned down into its full line or printing position.

In raising the platen frame the springs 30 serve to withdraw the roller 24; from contact with the aforesaid switch terminals thereby breaking the circuit to the lamps 15. V] hen the platen frame, however, is lowered onto the plate 10 an end of the controller 31 engages the post 2?" and carries the same downwardly to cause the roller 24 to maize contact between the spring switch terminal 20 and the terminals 2122 thus closing the circuit which includes the wires 16 and 1? to illuminate the lamps 15,

When the sensitized paper has been exposed to the light for a predeteri'nined or selected time the operator pushes against the finger piece 3i to cause the controller 31 to be moved into the position in which shown in Fig. 5 to accordingly release the post 27 whereupon the springs 30 act to instantaneously elevate the roller Ainto the position whereat it is shown in Fig. 6 thereby breakin the lamp circuit.

y thus breaking the circuit, the lamp light is quickly extinguished with an ab sence of arcing between the switch terminals and the roller 24 and that, too, without the necessity of elevating the frame 12.

As the platen is raised the spring 35 restores the controller 31 to its normal posi tion as shown in Fig. 1 so that when the frame 12 is again lowered the controller will encounter post 27 and force the same clownwardly to carry the roller into switch closing position.

It will be understood that changes in the form or arrangement of parts of this inven tion may be resorted to within the scope of the following claims.

What I claim is,--

1. In apparatus of the character described, a casing, a frame hinged to the top of said casing, a switch disposed below said frame, a vertically movable post extending through said casing, means connected with the said post for closing the switch when said post is moved downwardly, springs urging said post upwardly, and a trip member on said frame arranged to engage with and depress said post when the frame is lowered, said trip men'iber being arranged to be manually moved independently of said frame to release said post.

2. in apparatus of the character described, a casing, a frame hinged to the top of said casing, resilient switch terminals'depending in spaced relations from the top of said casing, a post movable vertically into said casing, a roller on the bottom end of said post for bridging said terminals when the post is moved downwardly, springs urging said post upwardly, a movable trip mem her on said frame, a spring for normally holding said trip member in a position to engage said post when the frame is lowered, and a fingerpiece on said trip member Whereby the same may be moved to release said post independently of any movements of the WILLIAM 1). W001).

Witnesses C. SHORTREED, JUSTINE Or'rorr. 

